There are times when I have been VERY tempted to collect these. Now they have announced the DC Action League, it's hard to fight the urge. How easy or difficult are some of the earlier ones to fine? I know I can still find several around me at retail.

Looking again at the original post, it sounds like the below are the single "exclusive" versions, with an asterisk on Blue Beetle since he was rereleased in the rerelease of the Batmobile that dropped Clock King. But of course most people would have to buy the Batmobile a second time to get him that way.

I think that's right. I have tried to keep that list updated really well with whatever is actually released. The only one that I kinda want to double check to make sure is this one, but I don't think it's been re-released in any other pack: